<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 800px;
            height: 400px;
            background-color: skyblue;
            display: flex;
            /* flex-direction:row;
            flex-wrap:wrap; */
            flex-flow:row nowrap ;
            /* justify-content: space-around; */
            align-items: stretch;
        }
        .box>div{
            width: 100px;
            height: 100px;
            background-color: red;
            /* flex-grow: 0; */
            /* flex-shrink: 1; */

            
        }
        .box>.item1{
            order: 4;
            /* flex-grow: 1; */
            /* flex-shrink: 0; */
            /* flex-basis: 300px; */
            flex: 1;
        }
        .box>.item2{
            order: 2;
        }
        .box>.item3{
            order: 3;
        }
        .box>.item4{
            order: 1;
        }
    </style>
</head>
<body>
    <div class="box">
        <div class="item1">1</div>
        <div class="item2" style="font-size: 30px;">2</div>
        <div class="item3">3</div>
        <div class="item4">4</div>
    </div>
</body>
</html>